Condensation induced water hammer driven sterilization

ABSTRACT

A method and apparatus ( 10 ) for treating a fluid or materials therein with acoustic energy has a vessel ( 14 ) for receiving the fluid with inner walls shaped to focus acoustic energy to a target zone within the vessel. One or more nozzles ( 26 ) are directed into the vessel ( 14 ) for injecting a condensable vapor, such as steam, into the vessel ( 14 ). The system may include a steam source ( 18 ) for providing steam as the condensable vapor from an industrial waste heat source. Steam drums ( 88 ) are disposed between the steam source ( 18 ) and nozzles ( 26 ) to equalize and distribute the vapor pressure. A cooling source ( 30 ) provides a secondary fluid for maintaining the liquid in the vessel ( 14 ) in subcooled conditions. A heating jacket ( 32 ) surrounds the vessel ( 14 ) to heat the walls of the vessel ( 14 ) and prevent biological growth thereon. A pressurizer ( 33 ) may operate the system at elevated pressures.

RELATED APPLICATION

This application claims priority to PCT application S/N PCT\US99\14760,filed Jun. 29, 1999 and provisional application S/N 60/091,341, filedJul. 1, 1998.

CONTRACTUAL ORIGIN OF THE INVENTION

This invention was made with United States Government support underContract No. DE-AC07-94ID13223, now Contract No. DE-AC07-99ID13727awarded by the United States Department of Energy. The United StatesGovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method and apparatus fortreating a fluid, such as the sterilization of water, or a materialtherein using acoustic energy in the form of cavitation, large amplitudeacoustic waves, and/or water hammer, generated by the rapid condensationof steam which is injected into the fluid. More particularly, itconcerns a method and apparatus for selectively injecting steam into areflector member disposed in the fluid which is shaped to focus anddirect the acoustic energy at a target zone within the chamber where theacoustic waves converge causing secondary cavitation, the chamber alsobeing shaped to focus the acoustic energy.

2. Background Art

A growing number of municipalities both inside and outside the UnitedStates are constrained to using drinking water supplies that come fromlocal rivers, lakes, and reservoirs that contain significant amounts ofhazardous micro-organismns. In many cases conventional chemicaldetoxification methods result in undesirable amounts of chlorine andchlorine byproducts in the treated water. Consequently, the municipaldrinking water supply is characterized by water that is unpalatable aswell as being a potential health problem. In recent years variousnon-chemical sonication schemes have been devised to replace or limitthe use of chemicals in water treatment procedures.

These sonication schemes utilize high-amplitude ultrasonic sound wavesto cause cavitation in a liquid. Cavitation occurs when thehigh-amplitude ultrasonic sound waves create gas-bubble cavities in theliquid. When the cavities collapse they produce intense localizedpressures. This cavitation may be induced to destroy liquid-borneorganisms, mix fluids or slurries, promote certain chemical reactions,and otherwise treat fluids or materials therein.

The high-amplitude ultrasonic sound waves are typically generated byelectrically driven piezoelectric or magnetostrictive transducers. Thetransducers are usually directed into a static liquid tank or a tank inwhich the liquid is circulated in order to sterilize objects within thetank, such as surgical instruments, or to sterilize the fluid itself Onedisadvantage of transducers is that they are typically confined to smallscale systems or batch processes.

Some larger scale systems for processing a continuous flow of water havebeen proposed. For example, U.S. Pat. No. 5,611,993, issued Mar. 18,1997, to Babaev, discloses a method which uses various tankconfigurations and inlet and outlet locations to cause temporary poolingof the water while a transducer for transmitting a high frequency soundwave is directed at the pooled water. U.S. Pat. No. 4,086,057, issuedApr. 25, 1978, to Everett, discloses a free jet of water directedagainst an ultrasonic vibrating surface. One disadvantage with thesesystems is that they are not practical for large scale disinfection of acontinuously flowing fluid. U.S. Pat. No. 5,611,993, issued Mar. 18,1997, to Babaev, discloses a plurality of opposing transducers. Onedisadvantage with some of these systems is their use of a larger numberof transducers which consequently utilize a larger amount of electricityto operate.

Other systems require additional processing steps to supplement thesonic process. For example, U.S. Pat. No. 5,466,425, issued Nov. 14,1995, to Adams discloses a system utilizing an applied voltage,ultraviolet radiation, and high frequency. Similarly, U.S. Pat. No.5,326,468, issued Jul. 5, 1994, to Cox, discloses cavitation induced bythe pressure drop across a nozzle throat and subsequent ultravioletradiation, ion exchange, and degassifying treatment. See also U.S. Pat.No. 5,494,585, issued Feb. 27, 1996, to Cox; and U.S. Pat. No.5,393,417, issued Feb. 28, 1995, to Cox. One disadvantage of thesesystems is their reliance on secondary treatments. Another disadvantageis their continued use of trstems utilize a cavitation chamber. Forexample, U.S. Pat. No. 5,519,670, issued May 21, 1996, to Walter,discloses a cavitation chamber in which acoustic pulses are generated byrepeatedly closing a valve, creating water hammer. The water hammerpropagates into the cavitation chamber through a diaphragm. See alsoU.S. Pat. No. 5,508,975, issued Apr. 16, 1996, to Walter. One problemwith this type of system is that repeatedly closing the valve fatiguesthe system components. Another problem with this type of system is theuse of a diaphragm which may become fatigued and fail. Another problemwith many systems is the complexity and number of components subject tofailure.

Another problem with many of the above systems is that the acousticenergy generated is inefficiently used. For example, the acoustic energyis indirectly propagated from a pipe system into a cavitation chamber.Other systems merely direct the transducer in the desired direction.U.S. Pat. No. 5,459,699, issued Oct. 17, 1995, to Walter, discloses aflexible, indented pipe to direct some of the water hammer in the pipeinto a surrounding fluid. Most of the acoustic energy in these systemsrandomly propagates through the system.

Although most systems utilize transducers to create cavitation, somesystems utilize the pressure drop across a nozzle to induce cavitationdownstream of the nozzle throat. See U.S. Pat. Nos. 5,326, 468;5,494,585; and 5,393,417. Traditionally, this type of cavitationsometimes occurs naturally in fluid systems and is generally consideredundesirable as it contributes to the fatigue and failure of systemcomponents.

In addition to micro-organisms, some fluids or fluid systems also havedifficulty with larger organisms. For example, the intake canals ofpower plants are clogged by zebra mussels. These intake canals typicallycontain large volumes of water, and conventional chemical treatments canprove to be expensive or environmentally unfriendly.

Furthermore, cavitation is also known to be useful in other processes inaddition to sterilization of fluids. Cavitation may also be used tosterilize other materials or objects in the fluid; promote chemicalreactions (sono-chemistry); treat wood fibers for paper pulp production;de-gas liquids; mix chemicals or slurries; or break down certaincompounds.

Therefore, it would be advantageous to develop a method and apparatuscapable of sterilizing a large amount of continuously flowing watersuitable for use with municipal water supplies, industrial waste water,or utility water supplies. It would also be advantageous to develop sucha method and apparatus which utilizes a novel acoustic source ratherthan traditional transducers. It would also be advantageous to developsuch a method and apparatus that is simple and has fewer components. Itwould also be advantageous to develop such a method and apparatus whichefficiently utilizes the acoustic energy. It would also be advantageousto develop a method and apparatus capable of handling larger organisms.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodand apparatus for sterilizing a large amount of continuously flowingwater suitable for use with municipal water supplies, municipal wastewater, and industrial food processing waste water.

It is another object of the present invention to provide such a methodand apparatus for treating other fluids and/or materials and objects inthe fluid; promoting chemical reactions; treating wood fibers for paperpulp production; de-gassing liquids; mixing chemicals or slurries; andbreaking down certain compounds.

It is another object of the present invention to provide such a methodand apparatus which utilizes a less expensive acoustic source, ratherthan traditional transducers.

It is another object of the present invention to provide such a methodand apparatus which is simple; has few moving parts; and has fewercomponents and is easily serviceable.

It is another object of the present invention to provide such a methodand apparatus which efficiently utilizes the acoustic energy.

It is another object of the present invention to provide a method andapparatus capable of handling larger organisms.

The above objects and others not specifically recited are realized in anumber of specific illustrative embodiments of an apparatus and systemfor treating a fluid and/or materials therein with acoustic energy. Forexample, the apparatus of the present invention is particularly wellsuited for sterilizing a continuous flow of water having microorganismstherein by destroying the micro-organisms with induced cavitation. Thesystem includes a vessel for receiving the fluid; a source ofcondensable vapor, such as steam; vapor headers for equalizing vaporpressure and protecting against liquid backflow; a directional nozzlearray for focusing and/or directing acoustic energy; a source of coolingfluid for maintaining subcooled conditions in the vessel; an optionalpressurizer or surge tank to either control pressure surges or operationat elevated pressures. The pressurizer option will be dictated by theengineering applications that are involved. Also, for biologicalapplications, an optional heating jacket will be employed tosufficiently heat the vessel walls to retard the growth of organismswhich may become attached to the walls.

The vessel has an inner wall defining a chamber. The chamber isconfigured to allow the fluid to pass therethrough in a continuousstream. The walls of the of the chamber are shaped or curved to focusand/or direct acoustic energy to a particular area of the chamberdefining a target zone. The vessel may be elongated and formed ofvarious elongated portions coupled together. The portions may havevarious cross sectional shapes for focusing the acoustic energy to thecommon target area. For example, the chamber may be formed by aplurality of portions having partially elliptical cross sections, eachwith a separate, outer focal point, and a common, inner focal pointdisposed in the target zone. The vessel may be elongated or create anelongated fluid path to create long enough dwell times such that thetarget products, such as micro organisms, spend enough time in theacoustic target zone to be destroyed.

The nozzle array has one or more nozzles or spargers coupled to thevessel and directed into the chamber. The nozzle array also has one ormore reflector members or shells. The reflector members have a curvedwall defining an indentation for focusing and/or directing acousticenergy. The reflector members may have one or a cluster of nozzlesdirected into the cavity. The indentations or cavities may be parabolicor circular shapes. An individual nozzle cluster and its immediatereflecting shell define a single acoustic source. The shells may haveleakage paths, or apertures formed therein, which allow cooling water tocirculate about the cavity and maintain subcooled conditions inside theshell.

The nozzles are configured for injecting a condensable vapor into thecurved indentations of the reflector members, and thus into the vessel.For example, the nozzle may be a steam sparger injecting steam. Theacoustic energy is created by the rapid condensation of the vapor in thepresence of the fluid. The acoustic energy is generated by localizedwater hammer shock waves as vapor bubbles implode. These localizedshocks will evolve into large amplitude acoustic pulses that will befocused on the target, or directed at the target zone. Additionalacoustic energy may also be induced by local turbulence and mechanicalloading on the nozzle and reflector members. This acoustic energy isfocused and/or directed at the target zone by the reflector members, andby the inner surfaces of the chamber. The acoustic waves converge withone another in the target zone inducing cavitation. The inducedcavitation may be used to treat the fluid or materials therein. Thesource of the condensable vapor is preferably a steam source supplyingwaste steam from a utility plant.

Each acoustic source, or steam sparger which its reflector member, issupplied by process steam via thermally insulated steam lines. Thesesteam lines are in turn connected to one or more common steam headers.For most applications, the steam flow in each line will be modulatedusing off the shelf technology. This modulation can be accomplished withhydraulic valves that area partially opened and closed in a periodicmanner. Self modulation schemes may also be employed and will bediscussed latersteam lines and associated check valves will be employedto control accidental liquid backflow. The vapor headers equalize thevapor pressure to the various nozzles. In addition, the headers act as ashock absorber in the event of backflow of liquid into the steam pipe.

The cooling system circulates a cooling fluid through the vessel tomaintain the vessel, or fluid to be treated, in subcooled conditions.Cooling of the main cavity and the spargers will be done with eitherpumped bulk flow across the main cavity, or the cooling fluid may belocally injected into the shell cavity of each acoustic source, or acombination of these methods. The coolant may be the same as the fluidwhich is treated.

For biological applications, the heating jacket surrounds the vessel andheats the walls of the vessel. The jacket may be a secondary, outershell disposed around the vessel, or it may be a pipe coiled about thevessel. The heating jacket keeps the walls heated to prevent biologicalgrowth thereon.

There are several possible geometric configurations for the resonancechamber which house the above mentioned array of acoustic sources, whichinclude but are not limited to cylindrical, spherical, and toridalconfigurations. The acoustic arrays will focus sonic energy in a targetzone of the cavity, where intense cavitation is induced. The cavitywalls will help focus this energy by reflecting scattered sound wavesthat are not directly absorbed in the target region. This target zonewill either have no contact or minimal contact with the resonancechamber to minimize cavitation induced wall erosion. Resonate modes thatare excited in the cavity will also help to enhance cavitation in thetarget zone. However, there will be cases where unwanted resonate modesimpinge directly on the cavity walls and are too intense. In thesesituations, baffles will be used to scatter sonic energy to limitlocalized wall cavitation erosion.

In addition, one or more individual acoustic sources described above canbe used for stand alone applications. Each sparger, or nozzle cluster,encased inside its reflecting shell along with its insulated processsteam supply line and cooling water intake line, if needed, can beplaced in some pre-existing hydraulic structure like an intake canal topower plant or water treatment facility. As an example, the stand aloneacoustic source or sources could be used to destroy organisms that clogthe intake filters to these facilities.

Finally, for specialized applications that are primarily non-biological,the cavitation chamber can be adapted to operate at elevated pressureswith the use of off the shelf pressurizer technology If the in flowingand out flowing liquid to the chamber is isolated form the openatmosphere, and the system is connected to a pressurizer, it is possibleto increase the ambient chamber pressure by several hundred atmospheres.An added benefit of using a pressurizer (even at low pressure) is thatthis system absorbs large amplitude pressure pulses that may otherwisecause pipe and/or vessel ruptures. At elevated pressures, the attendantincrease in cavitation implosion energy can increase aby as much as twoorders of magnitude.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by the practice of the invention withoutundue experimentation. The objects and advantages of the invention maybe realized and obtained by means of the instruments and combinationsparticularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the inventionwill become apparent from a consideration of the subsequent detaileddescription presented in connection with the accompanying drawings inwhich:

FIG. 1 is a schematic view of a continuous fluid sterilization system inaccordance with the principles of the present invention;

FIG. 2 is a top view of a fluid treatment apparatus in accordance withthe principles of the present invention;

FIG. 3 is a side, cross-sectional view of the fluid treatment apparatusof FIG. 2, taken along section 3—3;

FIG. 4 is a schematic view of the fluid treatment apparatus of FIG. 2;

FIG. 5 is schematic view of an alternative embodiment of a fluidtreatment apparatus in accordance with the principles of the presentinvention;

FIG. 6 is schematic view of an alternative embodiment of a fluidtreatment apparatus in accordance with the principles of the presentinvention;

FIG. 7 is schematic view of an alternative embodiment of a fluidtreatment apparatus in accordance with the principles of the presentinvention;

FIG. 7a is a side view of an alternative embodiment of a fluid treatmentapparatus in accordance with the principles of the present invention;

FIG. 8b is an end view of the fluid treatment apparatus of FIG. 8a;

FIG. 9a is side view of an alternative embodiment of a fluid treatmentapparatus in accordance with the principles of the present invention;

FIG. 9b is an end view of the fluid treatment apparatus of FIG. 9a;

FIG. 10 is a top view of an alternative embodiment of a fluid treatmentapparatus in accordance with the principles of the present invention;

FIG. 11 is a side, cross-sectional view of an alternative embodiment ofa water treatment device in accordance with the principles of thepresent invention; and

FIG. 12 is an end view of the water treatment device of FIG. 11.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles inaccordance with the invention, reference will now be made to theembodiments illustrated in the drawings and specific language will beused to describe the same. It will nevertheless be understood that nolimitation of the scope of the invention is thereby intended. Anyalterations and further modifications of the inventive featuresillustrated herein, and any additional applications of the principles ofthe invention as illustrated herein, which would normally occur to oneskilled in the relevant art and having possession of this disclosure,are to be considered within the scope of the invention claimed.

Referring to FIG. 1, a fluid treatment system or apparatus, indicatedgenerally at 10, of the present invention is shown for treating a fluidand/or materials or objects in the fluid with acoustic energy. Thesystem 10 is described and illustrated with respect to a specificembodiment for sterilizing a continuous flow of water havingmicro-organisms therein, such as a municipal water system. It is ofcourse understood that the system of the present invention may also beused for treating other fluids and/or materials therein. For example,the system may be used for promoting chemical reactions; treating woodfibers for paper pulp production; de-gassing liquids; mixing chemicalsor slurries; and breaking down certain compounds.

In addition, the term “acoustic energy,” as used herein, refers to andis intended to encompass various related or similar acoustic eventsgiven various terms, such as ultra-sonic radiation, acoustic waves,water hammer, cavitation, etc. For example, ultra-sonic radiationusually refers to high frequency wave energy or vibrations whichpropagate through a given medium at the speed of sound for that medium.Such ultra-sonic waves or vibrations usually have a frequency greaterthan the audible range, or greater than about 10-15 kHz. Water hammerusually refers to a high pressure pulse created when a rapidly flowingstream of fluid in a conduit is suddenly blocked. The kinetic energy ofthe flowing fluid is converted to a high pressure pulse. Cavitationoccurs in a liquid when the pressure at some point in the system isreduced to the vapor pressure of the liquid. Under such conditions,vapor bubble cavities form and then collapse. When each vapor cavityimplodes, intense localized pressure is generated that can be in the GParange. Subsequent vapor cavity collapse generates acoustic disturbanceswith a frequency spectrum that may have both ultra-sonic and sonicfrequency components. Also, for sufficient acoustic energy intensities,cavitation may be induced by a broad range of frequencies that includeboth sonic anc ultra-sonic ranges.

The system or apparatus 10 has a fluid vessel 14 for receiving a fluid;a condensable vapor source or vapor supply system 18 for providing orproducing a condensable vapor; vapor headers 22 for equalizing vaporpressure and protecting against liquid backflow; a directional nozzlearray 26 or acoustic source for focusing or directing acoustic energy; asource of cooling fluid or a cooling system 30 for maintaining subcooledconditions in the vessel; a heating jacket 32 for heating the walls ofthe vessel; and a pressurizer 33, all of which will be described ingreater detail below. The cooling source 30, heating jacket 32, andpressurizer 33 are optional and their use will be dictated by theparticular application and associated operating conditions.

The fluid vessel 14 is configured for receiving a fluid, such as watercontaining microorganisms. The vessel 14 has an inner surface 34, asshown in FIG. 3, defining a fluid chamber 38. The vessel 14 also has aprimary inlet 42 for allowing fluid to enter into the chamber 38 and aprimary outlet 46 for allowing fluid to exit the chamber 38. Baffles maybe placed at the vessel inlet to enhance turbulent mixing in the vessel.

The vessel 14 and chamber 38 are preferably elongated to allow forextended dwell times of the fluid and/or materials therein to maximizethe probability for cavitation exposure for a typical parcel of liquidentering the cavity. Thus, the flow of fluid defines a continuous andelongated fluid path 47 through the chamber 38 between the inlet 42 andthe outlet 46 and generally parallel and coaxial with a longitudinalaxis 48 of the chamber 38. It should be pointed out that the inlet 42and outlet 46 are not necessarily coaxial. Depending on other relevantkey design hydraulic parameters, such as Reynolds numbers and boundaryconditions, the inlet 42 and outlet 26 may be off set from the centralaxis of the chamber 38 to ensure more complete turbulent mixing. For offset designs, the flow path would not coincide with a target zonedescribed below. In addition, the vessel 14 and chamber 38 arepreferably sized to allow a large volume of fluid to flow therethrough.Thus, the system may be scaled to supply purified water for varioussized urban populations. Alternatively, the vessel 14 or chamber 38 maybe configured or shaped in various different ways as discussed morefully below.

The directional nozzle array 26 has a plurality of single acousticsources. Referring to FIG. 3, the nozzle array 26 advantageously has oneor more nozzles or spargers, such as a first nozzle or sparger 50 and asecond nozzle or sparger 51, for injecting a condensable vapor, such assteam, into the chamber 38. The nozzles 50 and 51 are coupled to thevessel 14 and directed into the chamber 38.

The nozzle array also advantageously includes first reflector member 52and second reflector member 53, coupled to the one or more nozzles orspargers, such as the first and second spargers 50 and 51, and disposedin the chamber 38. The reflector members 52 and 53 have a curved wall 54defining an open indentation or cavity 55. The reflector members 52 and53 are disposed in the chamber 38 and thus in the fluid so that thefluid is received within the cavities 55. The curved indentations 55surround the nozzles or spargers 50 and 51. The spargers 50 and 51 aredirected into the open cavities 55 such that the condensable vapor isinjected into the open cavities 55. The curved wall 54 is shaped tofocus and/or direct the acoustic energy created by the condensing vaporto a particular zone within the chamber 38 defining a target or killzone 56.

A single nozzle 50 or 51 may be directed into each reflector member 52or 53, or a cluster of nozzles may be directed into each reflectormember. Each reflector member and nozzle, or cluster of nozzles, definesa single acoustic source. The nozzle array 26 includes a plurality ofthese single acoustic sources, or nozzles/reflector members. The nozzlearray 26 may be located along a side or sides of the vessel 14 orchamber 38 and include a string of nozzles 50 and 51 with reflectormembers 52 and 53 along the length of the chamber 38, as shown in FIGS.1 and 3.

The injection of the condensable vapor into a liquid environment resultsin an almost immediate localized bubble collapse with an attendantrelease of intense acoustic energy. The injection of the condensablevapor is modulated. The reason for modulating the injection is two fold.First, the modulation allows continuous replacement of subcooled waterin a cavitation zone near the steam nozzle outlets. Second, themodulation allows for impulsive loading that augments the excitation ofnormal modes in the cavity, or optionally near specially designed metalstructures that are designed to oscillate at high frequencies. Forexample, the acoustic energy may be used to kill or destroymicro-organisms in water, thus sterilizing the water.

Referring to FIG. 4, the inner surface 34 of the chamber 38 ispreferably shaped to focus and/or direct the acoustic energy in thechamber 38 to the target zone 56. The elliptical surface 34 of thechamber 38 is designed to enhance the focusing of the acoustic energythat has not been directly absorbed in the target zone 56. The innersurface 34 of the chamber 38 preferably forms at least two parallel,adjoining portions, such as a first portion 60 and a second portion 62.Thus, the two portions 60 and 62 define the fluid channel 38 with thetarget zone 56 between the two portions 60 and 62. Each portion 60 and62 has an inner surface 66 and 68 which forms a curve to focus and/ordirect the acoustic energy at the target zone 56. Thus, the innersurface 34 of the chamber 38 has at least two curved portions 60 and 62which are shaped to focus the acoustic energy to the target zone 56.

The injection of the condensable vapor into a liquid environment resultsin an almost immediate localized bubble collapse with an attendantrelease of intense acoustic energy. The injection of the condensablevapor is modulated. The reason for modulating the injection is two fold.First, the modulation allows continuous replacement of subcooled waterin a cavitation zone near the steam nozzle outlets. Second, themodulation allows for impulsive loading that augments the excitation ofnormal modes in the cavity, or optionally near specially designed metalstructures that are designed to oscillate at high frequencies. Forexample, the acoustic energy may be used to kill or destroymicro-organisms in water, thus sterilizing the water. The curved innersurface 66 and 68 of each of the two portions 60 and 62 of the chamber38 preferably form an ellipse, or are elliptical. Thus, the chamber 38is formed by two elongated portions 60 and 62 having elliptical crosssections coupled together. The first portion 60 has a first outer focalpoint 72 and the second portion 62 has a second outer focal point 74. Inaddition, each portion 60 and 62 has another focal point 76 located in acommon area, namely the target zone 56. Thus, each portion 60 and 62 hastwo focal points including an inner focal point 76 in the target zoneand an outer focal point 72 and 74. The inner focal points 76 arelocated near the center or middle of the chamber 38 while the outerfocal points 72 and 74 are located near the outside or circumference ofthe chamber 38. The focal points are preferably defined by the focalpoints of the elliptical cross-sections of the adjoining portions. Thefocal points of the elliptical cross-sections are also focal axes of theelongated, cylindrical, elliptical chamber 38.

The nozzle array. 26 defines a first nozzle array and generates acousticenergy along the first elliptical focal axis 72 in the chamber 38. Thefirst nozzle array 26 is a plurality of the first nozzles 50 and firstreflector members 52. A second nozzle array 27, symmetrical with thefirst array 26, generates acoustic energy along the second ellipticalfocal axis 74. The second nozzle array 27 is a plurality of the secondnozzles 51 and second reflector members 53. The first and second focalaxes 72 and 74 define first and second axial source locations which areseparate from one another and separate from the target zone. Thus,acoustic energy created at the first and second focal points 72 and 74is directed and focused to the common second focal point 76 or targetzone 56. Secondary cavitation is caused as the acoustic waves convergewith one another in the target zone 56. Thus, the target zone 56 is alsoa cavitation zone. The secondary cavitation and acoustic energy may beused to destroy or kill micro-organisms within water.

The chamber 38 geometry can be employed to support resonate cavity modesand to focus acoustic pressure waves. Induced cavity normal acousticmodes can either enhance or degrade system performance depending on theparticular type of modes generated. Pressure waves created by the rapidcondensation of the vapor as it contacts the fluid propagate through thechamber. The shape of the inner surface 34 of the chamber 38 directsand/or focuses the pressure waves so that cavitation occurs as thepressure waves converge with one another. Thus, it is desirable tocreate, direct, and focus the waves or acoustic energy at a common area,such as the target zone 56, where cavitation may be used to destroymicro-organisms, or otherwise treat the fluid or material therein. Theprimary acoustic waves intersect directly at the common focal point ortarget zone. The secondary acoustic waves bounce off the cavity wallsand are combined at the common focal point or target zone.

The vessel 14 also has end plates 84 disposed on both ends of the vessel14 with baffles 86 coupled thereto to scatter and absorb unwantedresonate axial wave modes that do not pass directly through the targetzone, as shown in FIG. 2. Depending on the circumstances, end platebaffle covering may be partial or complete. These axial wave modes mayinduce unwanted cavitation outside of the intended cavitation zone thatcan defocus energy aimed at the target zone and induce cavitation wallerosion. An alternative scheme for suppressing axial cavity modes is toredesign the axial geometry of the resonating chamber such that flat endplates are replaced with hemispherical end caps 88, as shown in FIG. 2.On the other hand, induced damped radial cavity modes directed betweenthe first and second focal points 72 and 74 and that converge on thecentral target zone 56 are desirable and enhance system operation ifabsorption in the target zone keeps acoustic intensities low at theopposite right and left ends of the cavity 38, so as to avoid wallcavitation erosion bounded by the transmission zone 84.

Referring to FIGS. 1 and 2, the directional nozzle arrays 26 and 27 areconfigured with a cluster of nozzles or spargers 50 and 51 surrounded byreflector members 52 and 53. The nozzle arrays 26 and 27 are directed atthe axial source locations 72 and 74 which extending along the length ofthe vessel 14 and chamber 38. The acoustic energy from these sourcelocations 72 and 74 propogate through the transmission zone 84 andconverge at plurality of target zones 56 that extend along the length ofthe chamber 38. The fluid flow path 47 extends along the longitudinalaxis 48 of the chamber 38, and is generally within or coaxial with thetarget zone 56. Thus, as the fluid passes through the chamber 56, it maybe exposed at various and multiple locations to multiple or continuousapplications of acoustic energy and cavitation.

Referring to FIGS. 1-3, a header 22 is coupled to the nozzle array 26,or the nozzles or spargers 50 and 52, process lines 86 for communicatingthe vapor from the header 22 to the nozzles 50 and 52. The process lines86 are preferably straight, or free of elbows and the like, to preventwater hammer damage. The header 22 is a pressurized cylindrical drumhaving a cavity 88 formed therein for receiving the vapor. The header 22equalizes pressure to each supply line 86. In addition, the header alsoserves as a shock absorption reservoir to dissipate pressure waves thatare generated when flow through the supply lines is modulated or foraccidental liquid backflow. Check valves may be located in each supplyline to limit damage caused by accidental liquid backflow.

The vessel 14 also has a secondary inlet 90 for allowing a cooling fluidto enter into the chamber 38 and a secondary outlet 92 for allowingcooling fluid to exit the chamber 38. The cooling fluid helps maintainsubcooling conditions in the chamber 38. The cooling fluid may be thesame as the fluid to be treated, such as water. In addition, the coolingfluid may or may not be separated from the fluid to be treated. A pipe,not shown, may extend between the secondary inlet and secondary outletso that the cooling fluid does not mix with the fluid to be treated. Inaddition, the nozzle arrays may be cooled by a distribution of branchingcooling lines 93 that individually inject cooling water into thevicinity of each nozzle 50 and 52. The secondary inlet 90 receives thecooling fluid from a source of cooling fluid 30. The cooling fluid maybe pumped from the source 30 to the vessel 14 by a pump 94.

The cooling fluid and source 30 form a cooling system for removingthermal energy deposited in the vessel 14 from the vapor, which may beheated. The cooling system maintains uniform subcooling conditions inthe chamber 38 or the transmission zone 84. The pump 94 circulates thecooling fluid to ensure that local bulk temperature cond 52 aremaintained in a subcooled state. The source of cooling fluid 30 mayinclude heat exchangers in a cooling pond. Cooling also occurs as aconsequence of the passage of the fluid to be treated through thechamber 38.

The heating jacket 32 is disposed about at least a portion of the vessel14. The heating jacket heats the vessel 14, or the vessel's walls, toprevent the growth of biological substances thereon. It will beappreciated that the existence of micro-organisms in the fluid, and thusthe vessel, in combination with the heat from the steam may facilitatethe growth of these biological substances on the walls of the vessel.Thus, the heating jacket heats the walls of the vessel to a temperaturein which the biological substances may not grow. The heating jacket 32may be a secondary vessel or shell 98 formed about the vessel 14 throughwhich a heated fluid may be circulated about the vessel 14, as shown onthe left hand side of the vessel in FIG. 1 and in FIG. 3. Alternatively,the heating jacket 32 may be a pipe 102 coiled about the vessel 14through which a heated fluid is circulated, as shown on the right handside of the vessel in FIG. 1. The heated fluid may be steam and suppliedwith the same process steam used to power the acoustic sources.

In the preferred embodiment, the apparatus or system 10 is configured tosterilize a continuous stream of water containing micro-organisms. Thus,a constant flow of water is passed through the vessel 14 and chamber 38.The water is preferably pre-treated before entering the chamber so thatit is subcooled, de-aerated, and pre-filtered.

The chamber 38 is sized to meet the purified water requirements of agiven location. For example, the chamber 38 may be sized to supplypurified water to hundreds of thousands of people. For the example, apopulation of one hundred thousand people whose nominal dailyconsumption is 100 gallons per person per day is assumed. (This is afigure of merit for estimated world wide consumption. Actual U.S.consumption is approximately 180 gallons per person per day.) Thus, thebase line per-day treatment capacity for the system is about 10⁷ gallons(or 3.75×10⁴ m³). The acoustic energy loads needed to completelysterilize a cubic meter of water is estimated to be on the order ofabout 5×10⁵ J/m³. Thus, the acoustic daily time average power loads ofat least 2.17×10⁵ watts are needed to service drinking water for apopulation of 10⁵ people. It should be noted that energy requirementsfor boiling an equivalent amount of liquid is several orders ofmagnitude higher relative to acoustic sterilization. In addition,volumetric flow rates are on the order of 1 m³/sec (16,000 gpm). Forthis example, the target zone has a cross sectional area ofapproximately 1 m². The length of the target zone, and thus the vessel,is approximately 50 m. The ambient operating pressure is maintainedbetween 1 and 3 atmospheres. At one atmosphere, the cavitation powerthreshold is about 3000 w/m². For 100% absorption in the target zone,this gives a total energy absorption rate on the order of 0.5 MW orenergy densities on the order of 10⁴ watts/m³. For a 1 m³ (264 gallons)parcel of liquid to transit the absorption zone moving at 1 m/s, thisresults in deposition rates on the order of 0.5 MJ for 50 sec dwelltimes in the kill zone. Actual net residency time in the cavity itselfis longer because of turbulent motion. Therefore, the vessel and chamberare sized for the commercial sterilization of a municipal water supply.

In addition, for such a system the source of condensable vapor 18 is asteam source, and the header 22 is a steam drum. The steam source 18preferably utilizes waste heat from a conventional power plant, such asconventional open cycle gas turbine plants, to generate steam. Otherpossible waste heat sources include industrial waste treatmentfacilities that employ plasma torch technologies to dispose of largequantities of solid wastes.

The cooling system may use counter current external cooling loops drivenby pumps. The pumps may be one or more steam turbine high capacitycentrifugal pumps driven by part of the waste process steam feed fromthe steam headers. Without local subcooling, acoustical energyconversions to be less efficient. In addition, uncontrolled heat-ups inthe nozzle region may increase local vapor pressure making it easier tocavitate liquid in the surrounding transmission zone. Unwantedcavitation in the transmission zone will de-focus and absorb energy thatis intended for the absorption zone.

Therefore, such a system will limit the use of chlorine and otherchemicals to disinfect water relative to large scale municipal watertreatment methods. The results include safer and more palatable drinkingwater. In addition, such a system utilizes a less expensive source ofacoustic energy. Preferably using industrial waste heat to generatesteam. Furthermore, such a system efficiently utilizes the acousticenergy by focusing or directing it towards the target zone.

It is of course understood that the above described system, and theconfigured chamber, may be used to treat other fluids or materialstherein. For example, the above system or chamber may be used forpromoting chemical reactions; treating wood fibers for paper pulpproduction; de-gassing liquids; mixing chemicals or slurries; breakingdown certain compounds; and destruction of biological munitions.

More exotic and problematic applications include operating thecavitation chamber at high or ultra high pressures with the use of apressurizer 33 and state of the art structural and materials engineeringtechnologies. These systems may also have to operate in extremely hot orcold temperature environments. Cavitation implosions can focus energy byas much as 12 orders of magnitude. Also, cavitation induced implosionsin an elevated pressure environment may be sufficient to locally heatmaterial to induce either fusion or fission reactions. Thus, whencurrent structural technology becomes capable of accommodating suchelevated operating pressures or severe temperature conditions it may bepossible to use cavitation technology to sustain a break-even nuclearexothermic reaction that is practical to generate useful energy. Liquidsdeployed in such a device could include heavy water, cryogenic liquids,mixtures of deuterium and tritium, or molten metals containing fissileelements.

In addition, it is understood that the above described chamber may beconfigured in various different ways to focus and/or direct the acousticenergy in an efficient manner, some of which are described below.

Referring to FIG. 5, an alternative embodiment of a vessel 110 is shownwith an inner surface 112 defining a chamber 114 having two opposingportions 116 and 118 with curved cross sections. The curved portions 116and 118 direct acoustical energy created by the injection of acondensable vapor from the nozzles 50 and 52 to a target zone 120.

Referring to FIG. 6, an alternative embodiment of a vessel 130 is shownwhich is similar to the embodiment of FIG. 3, but has a third elongatedportion 132. The third portion 132 is parallel with and coupled to thefirst and second portions 60 and 62. The third portion 132 may beperpendicular to the first and second portions 60 and 62, as shown, orall three portions may be configured with equal angular spacingtherebetween. The third portion 132 preferably has a curved innersurface 134 with a parabolic cross section. Thus, the third portion 132has a third outer focal point 136 and another focal point in common withthe first and second portion located in the target zone 56.

In addition, a third nozzle 138 is directed to inject a condensablefluid at the third focal point. Therefore, the acoustic energy generatedfrom the injection of a condensible fluid from three separate points isdirected and focused at the target zone. A generalization of the abovescheme can be extended to an arbitrary number of overlapping cylindricalelliptical cavities that share a common focal point which form a flowerpedal or lotus like pattern.

Referring to FIG. 7, an alternative embodiment of an apparatus 130 isshown in which the vessel 14 has two portions 132 and 134 of ellipticalcross section that share a common inner focal point, as in FIG. 4, butinstead are volumes bounded by surfaces of revolution about the axly bysurfaces of revolution about the axis connecting the source locations 72and 74. The two portions 132 and 134 may be non-elliptical. In addition,multiple nested sets of these portions sharing a common focal point maybe generated. For the case of surface of revolution about the outerfocal points 70 and 72, an identical overlapping set of portions that isperpendicular to the page may be added to again generate a lotus likepatterned cross section. In this example, acoustic energy will befocused from the multiple portions to a common target zone.

Referring to FIGS. 8a and 8 b, an apparatus 140 has a vessel 14 with aninner surface forming an elongated cylinder. A plurality of acousticsources 142, or nozzle arrays 26, are disposed along the length of thecylinder, as shown in FIG. 8a, and about the circumference of thecylinder, as shown in FIG. 8b. The acoustic sources 142 have nozzlesdirected to inject the condensable vapor into the cylinder. Becausemultiple acoustic sources 142 are disposed about the circumference ofthe cylinder, the acoustic energy created by the rapid condensation ofthe vapor will converge towards the center of the cylinder, orlongitudinal axis of the vessel 48 as shown in FIG. 8a, defining atarget zone 56 generally extending the length of the cylinder andcoaxial with the longitudinal axis. The acoustic energy may alsopropagate throughout the cylinder. It is of course understood that thecylinder may have a cross sectional shape that is right circular, or mayhave some other shape, such as elliptical, etc.

Referring to FIGS. 9a and 9 b, an apparatus 150 has a vessel 14 with aninner surface forming a sphere A plurality of acoustic sources 152, ornozzle arrays 26, are disposed around the sphere. The acoustic sources152 have nozzles directed to inject the condensable vapor into thesphere. Because multiple acoustic sources 152 are disposed about thesphere, the acoustic energy or shock waves will converge towards thecenter of the sphere defining a target zone 56. The acoustic energy mayalso propagate throughout the sphere. Referring to FIG. 10, an apparatus160 has a vessel 14 with an inner surface forming a torus, or donut. Thefluid inlet 42 and fluid outlet 46 may be disposed on opposing ends ofthe torus, forming the fluid flow path 47 to split and have one portionflow around one half of the torus and another portion flow around theother half. A plurality of acoustic sources 162, or nozzle arrays 26,are disposed around the torus with some being disposed on the outside164 of the torus and some being disposed on the inside 166 as shown. Theacoustic sources 162 may also be disposed about the circumference of thecross section of the torus, similarly to that of the cylinder in FIGS.8a and 8 b. The torus may have a cross-sectional shape that is rightcircular. Alternatively, the cross-section of the torus may beelliptical, etc. Furthermore, the cross-section of the torus may becomposed of multiple, partial ellipses coupled together, similar tothose of FIGS. 4 and 6.

A method for sterilizing water having micro-organisms therein using theapparatuses or system described above includes causing the water to betreated to flow into an elongated vessel. The vessel has an innersurface shaped to focus acoustic energy. Steam is selectively injectedby spargers into the vessel at points along the length of the vessel.The steam rapidly condenses in the presence of the water creatingacoustic energy. The acoustic energy is focused by reflector membersdisposed about the spargers to a specific zone within the vessel andextending the length of the vessel defining a target zone. The innersurface of the vessel also focuses and directs the acoustic energy tothe target zone.

While the above described and illustrated systems or apparatuses areparticularly well suited for use with continuously flowing fluids, andalso may be readily adapted for stand alone purposes. For example,situations may occur in which it is difficult or impossible to induce adesired fluid or material to flow into and through the chamber. Such asituation exists with respect to the formation of zebra mussels onscreens. While the water surrounding the mussels and the screens isreadily induced into a chamber, the mussels are fixed to the screens.

Referring to FIGS. 11 and 12, a device for treating a fluid or materialtherein with acoustic energy is shown, indicated generally at 200. Thedevice 200 is similar in many respects to the acoustic source in theapparatuses or systems described above, but may be positioned or locatedindependent of a vessel or chamber, such that it may be disposed at adesired location where the liquid or materials are located. The device200 is analogous to conventional electrically powered loud speakers. Inaddition, the device may even be portable or moveable such that it maybe disposed at will with respect to larger volumes of fluid.Alternatively, the device 200 may be permanently installed in a chamberdescribed above as an acoustic source.

The device 200 has a reflector urface 212 forming an indentation 214.The reflector member 210 is disposed in the fluid to be treated and thefluid fills the indentation 214. A nozzle or sparger 216 is coupled tothe reflector member 210 and directed into the indentation 214. Thenozzle or sparger 216 may be a nozzle or sparger assembly. In addition,the internal geometry of the nozzle or sparger 216 may be based oneither smooth or abrupt area nozzle/sparger designs. However, for chokedflow discharge, a nozzle geometry with a smooth area change isanticipated to be the most efficient way of injecting steam into thereflector member.

The nozzle 216 injects a condensable vapor, such as steam, into the isindentation. As discussed above, acoustic energy is generated by therapid condensation of the vapor as it contacts the fluid. A plurality ofnozzles or spargers 218 may be coupled to the reflector member anddirected into the indentation, as shown in FIG. 12. A supply line orpipe 220 is coupled to the nozzle 216 or plurality of nozzles 218 forsupplying the condensable vapor.

Vapor flowing through the process steam supply lines 220 may bemodulated by the partial closing and opening of hydraulic valvesupstream of the spargers. Insulating jackets may surround each processline to prevent premature condensation and energy loss. Also, a muchlarger diameter cylindrical insulating jacket may be wrapped around theentire device 200, with an opening at the cavity of the reflectormember.

A ring-shaped pipe 222 may be disposed around the reflector member 210and coupled between the supply line 220 and the plurality of nozzles 218to distribute the vapor from the supply line 220 to the nozzles 218. Asupport member 224 may also be attached to the reflector member 210 tosupport the reflector member 210 and/or locate and position thereflector member 210. The support member 224 may be hollow and in fluidcommunication with the cavity 214 for conducting a cooling fluiddirectly into the cavity. Thus, a cooling fluid, such as water, may beinjected directly into the cavity 214 and near the sparger 216. Inaddition, bypass holes 226 may be formed in the reflector member 210 sothat fluid may pass though the holes 226 and thus through the cavity214. Thus, if the device 200 is submerged in a flowing liquid, theliquid may flow through the reflector member 210 and past the sparger216 to maintain subcooling inside the cavity 214.

The inner wall or surface 212 of the reflector member 210 may be shapedas desired to direct and/or focus the acoustic energy at a desiredtarget area generally outside of the cavity 214. Preferred reflectorshapes include parabolic, conical, and circular shapes. Thus, thereflector member 210 may be located and directed towards a desired area.For example, the device 200, or a plurality of devices, may be fixed atvarious locations around an intake subject to mussel accumulation. Steammay be supplied to the nozzles 216 and 218 to be injected into thecavity 214. The acoustic energy created by the rapid condensation of thesteam is directed by the curved wall 212 of the reflector member 210 atthe mussels. Alternatively, the device 210 may be moved as desired totreat a particular area. The wall 212 may be shaped as a parabola, acircle, a cylinder, etc. The device 210 may have a single indentation214 forming a cup-like indentation, as shown, to focus the acousticenergy. Alternatively, the device may have an elongated indentation,forming a half cylinder, with a plurality of nozzles extending along thelength of the indentation to treat a longer or wider area.

Thus, it will be recognized that the device 200 is similar to a singleunit of the nozzle array 26 and that the device 200 may be configured asan elongated partial cylinder with a plurality of nozzles to form anozzle array 26 as an integral part of the vessels described above, ormay be used independently.

The above acoustic source emits acoustic pulses that contain a range ofdiffering frequency components. Generally, lower frequency componentshelp to facilitate long range penetration with minimal acousticdissipation, while high frequency components help to maximize the rateof secondary cavitation in a target zone. In order to optimize thisfrequency spectrum for a particular application, several other possibledesign options can be employed to modify this frequency spectrum whichinclude modification to nozzle hole sizes, nozzle positions, usingspecial resonating cavities in the stream lines upstream of the nozzlechoke planes and injection points into the liquid cavity, and modifyingthe nozzle bodies themselves to interact and vibrate with localizedimploding vapor cavities. Design modifications to the nozzle bodies mayentail adding metal fins or flexible diaphragms to these members toinduce high frequency vibrations. In addition, such design modificationsmust be balanced against the need to minimize local wall cavitationerosion and other forms of material fatigue in and about the vaporimplosion zone in the reflector cavity.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the presentinvention. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the spiritand scope of the present invention and the appended claims are intendedto cover such modifications and arrangements. Thus, while the presentinvention has been shown in the drawings and fully described above withparticularity and detail in connection with what is presently deemed tobe the most practical and preferred embodiment(s) of the invention, itwill be apparent to those of ordinary skill in the art that numerousmodifications, including, but not limited to, variations in size,materials, shape, form, function and manner of operation, assembly anduse may be made without departing from the principles and concepts setforth herein.

I claim:
 1. An apparatus for treating a fluid with acoustic energy, theapparatus comprising: a vessel having an inner surface defining achamber configured for receiving a fluid, the vessel having an inlet andoutlet; at least one nozzle coupled to the vessel and directed into thechamber, the at least one nozzle configured for injecting a condensablevapor into the chamber to create acoustic energy by rapid condensationof the vapor as it contacts fluid present within the chamber; and astructure affixed to the at least one nozzle and configured for at leastdirecting the acoustic energy generated by the rapidly condensing vaportoward a particular zone within the chamber defining a target zone. 2.The apparatus of claim 1, wherein the structure affixed to the at leastone nozzle comprises at least one reflector member coupled to the atleast one nozzle and having a curved wall defining an indentation forfocusing and/or directing the acoustic energy toward the target zone. 3.The apparatus of claim 1, wherein the inner surface of the vessel isshaped to at least direct the acoustic energy toward the target zone. 4.The apparatus of claim 3, wherein the inner surface of the vesselcomprises at least two adjoining portions that define a fluid channelwith the target zone therein, and wherein each portion has an innersurface which forms a curve to at least direct the acoustic energytoward the target zone.
 5. The apparatus of claim 4, wherein the curveformed by the inner surface of each portion is elliptical.
 6. Theapparatus of claim 4, wherein the curve formed by the inner surface ofeach portion is parabolic.
 7. The apparatus of claim 3, furthercomprising: a first nozzle directed to inject the condensable vapor at afirst location within the chamber; a second nozzle directed to injectthe condensable vapor at a second location within the chamber, thesecond location separated from the first location; wherein the innersurface of the vessel has a first curved portion shaped to direct theacoustic energy generated proximate to the first location toward thetarget zone, and a second curved portion shaped to direct the acousticenergy generated proximate to the second location toward the targetzone, the target zone separated from both the first and secondlocations.
 8. The apparatus of claim 3, wherein the inner surface of thevessel forms an elongated cylinder, and further comprising a pluralityof nozzles disposed around a circumference of the inner surface andalong the length of the inner surface.
 9. The apparatus of claim 3,wherein the inner surface of the vessel is spherical, and furthercomprising a plurality of nozzles disposed around the inner surface. 10.The apparatus of claim 3, wherein the inner surface of the vessel formsa torus, and further comprising a plurality of nozzles disposed aroundthe inner surface.
 11. An apparatus for sterilizing water containingmicro-organisms by destroying the micro-organisms with acoustic energy,the apparatus comprising: a vessel having an inner surface defining achamber configured for receiving a fluid, the vessel having an inlet andoutlet; and at least one acoustic source coupled to the vessel anddirected into the chamber, the at least one acoustic source having atleast one steam sparger coupled to the vessel and directed into thechamber, the at least one acoustic source also having at least onereflector member disposed in the chamber and coupled to the at least onesteam sparger, the reflector member having a curved wall defining anindentation for, at least directing the acoustic energy toward aparticular zone within the chamber defining a target zone.
 12. Theapparatus of claim 11, wherein the inner surface of the vessel forms afirst elongated portion having a partially elliptical cross section anda second elongated portion parallel with the first portion having apartially elliptical cross section coupled to the second portion, andwherein the at least one acoustic source comprises: a first steamsparger and a first reflector member, the first steam sparger configuredfor injecting steam into the first portion generally within the firstreflector member the first steam sparger and first reflector member eachsized and configured to at least direct the acoustic energy created bythe rapid condensation of the steam toward the target zone; and a secondsteam sparger and a second reflector member, the second steam spargerconfigured for injecting steam into the second portion generally withinthe second reflector member the second steam sparger reflector membereach sized and configured to at least direct the acoustic energy createdby the rapid condensation of the steam toward the target zone.
 13. Theapparatus of claim 12, wherein the inner surface forms a third elongatedportion having a partially elliptical cross section coupled to the firstportion and the second portion, the third portion having a third outerfocal point; and a third steam sparger with a third reflector member,the third steam sparger configured for injecting steam into the thirdportion and generally within the third reflector member, the third steamsparger and third reflector member each sized configured to at leastdirect the acoustic energy created by the rapid condensation of thesteam toward the target zone.
 14. The apparatus of claim 12, wherein thevessel has a baffles disposed at opposing ends of the vessel sized andconfigured to inhibit a pressure or cavitation condition.
 15. Theapparatus of claim 12, wherein the vessel has opposing ends with curvedwalls sized and configured to inhibit a pressure or cavitationcondition.
 16. An apparatus for treating a fluid with acoustic energy,the apparatus comprising: a vessel having an inner wall defining achamber configured for receiving a fluid, the vessel having an inlet andoutlet; at least one steam sparger coupled to the vessel and directedinto chamber, the at least one steam sparger configured for injectingsteam into the chamber to create acoustic energy by rapid condensationof the steam as it contacts fluid within the chamber; a steam drumcoupled to the at least one steam sparger by at least one steam supplyline extending between the drum and the at least one steam sparger, thesteam drum defining an interior cavity configured for receiving steamand equalizing steam pressure to the at least one steam sparger.
 17. Theapparatus of claim 16, wherein the at least one steam supply line issubstantially straight to protect against water hammer damage.
 18. Theapparatus of claim 16, further comprising a source of steam forproviding steam to the steam drum.
 19. The apparatus of claim 18,wherein the source of steam utilizes waste heat to provide steam.
 20. Anapparatus for treating a fluid with acoustic energy, the apparatuscomprising: a vessel having an inner surface defining a chamberconfigured for receiving a fluid, the vessel having a primary inletconfigured for allowing fluid to enter into the chamber and a primaryoutlet configured for allowing fluid to exit the chamber, the vesselalso having a secondary inlet configured for allowing a cooling fluid toenter the chamber; and at least one steam sparger coupled to the vesseland directed into the chamber, the at least one steam sparger configuredfor injecting steam into the chamber to create acoustic energy by rapidcondensation of the steam as it contacts fluid within the chamber. 21.The apparatus of claim 20, further comprising a source of cooling fluidand a delivery structure for introducing the cooling fluid into thevessel.
 22. An apparatus for treating a fluid with acoustic energy, theapparatus comprising: a vessel having an inner surface defining achamber configured for receiving a fluid, the vessel having an inlet andoutlet; at least one steam sparger coupled to the vessel and directedinto chamber, the at least one steam sparger configured for injectingsteam into the chamber such that acoustic energy is created by the rapidcondensation of the steam as it contacts fluid within the chamber; awall heating structure disposed about at least a portion of the vesselfor heating the inner surface to biological growth thereon.
 23. Theapparatus of claim 22, wherein the vessel is a primary vessel, andwherein the wall heating structure comprises a secondary vessel formedabout the primary vessel defining a space therebetween configured forreceiving steam.
 24. The apparatus of claim 22, wherein the wall heatingstructure comprises a steam pipe coiled around the vessel and configuredfor receiving steam and transferring heat therein through the steam pipeand vessel to the inner surface.
 25. A system for treating a fluid withacoustic energy, the system comprising: a vessel having an inner walldefining a chamber configured for receiving a fluid, the vessel having aprimary inlet configured for allowing fluid to enter into the chamberand a primary outlet configured for allowing fluid to exit the chamber,the vessel also having a secondary inlet configured for allowing acooling fluid to enter into the chamber; at least one steam spargercoupled to the vessel and directed into the chamber, the at least onesteam sparger configured for injecting steam into the chamber to createacoustic energy by the rapid condensation of the steam as it contactsfluid within the chamber; a steam drum coupled to the at least one steamsparger by at least one steam supply line extending between the drum andthe at least one steam sparger, the steam drum defining an interiorcavity configured for receiving steam and equalizing steam pressure tothe at least one steam sparger; and a wall heating structure disposedabout at least a portion of the vessel for heating the inner surface toinhibit biological growth thereon.
 26. The system of claim 25, furthercomprising a source of cooling fluid and a delivery structure forintroducing the cooling fluid into the vessel.
 27. The system of claim25, further comprising a source of steam for providing steam to thesteam drum, the steam spargers and the wall heating structure.
 28. Thesystem of claim 27, wherein the source of steam utilizes waste heat toprovide steam.
 29. The system of claim 25, wherein the vessel is aprimary vessel, and wherein the wall heating structure comprises asecondary vessel formed about the primary vessel defining a spacetherebetween configured for receiving steam.
 30. The system of claim 25,wherein the wall heating structure comprises a steam pipe coiled aroundthe vessel and configured for receiving steam and transferring heattherein through the steam pipe and vessel to the inner surface.
 31. Thesystem of claim 25, wherein the inner surface of the vessel forms afirst partially elliptical portion and a second partially ellipticalportion coupled to the second portion and wherein the at least one steamsparger comprises: a first steam sparger coupled to the vessel at thefirst portion, the first steam sparger configured for injecting steaminto the first portion to at least direct the acoustic energy created bythe rapid condensation of the steam toward the target zone; and a secondsteam sparger coupled to the vessel at the second portion, the secondsteam sparger configured for injecting steam into the second portion toat least direct the acoustic energy created by the rapid condensation ofthe steam toward the target zone; wherein the first steam sparger andsecond steam sparger are sized and configured to caused secondarycavitation in the target zone as the acoustic energy created by thefirst steam sparger and the second steam sparger interferes in thetarget zone.
 32. A device for treating a fluid with acoustic energy, thedevice comprising: a reflector member having a curved wall forming anindentation, the reflector member configured for disposition in a fluidand receiving the fluid within the indentation; at least one steamsparger coupled to the reflector member and directed into theindentation, the at least one steam sparger configured for injectingsteam into the indentation, wherein the curved wall of the reflectormember is shaped to at least direct acoustic energy created by rapidcondensation of the steam in the presence of the fluid.
 33. The deviceof claim 32, further comprising a delivery structure for injecting acooling fluid into the indentation of the reflector member.
 34. Thedevice of claim 32, further comprising one or more holes formed in thecurved wall of the reflector member for allowing the fluid to pass. 35.A method for treating a fluid, the method comprising: disposing a fluidinto a vessel having an inner surface; selectively injecting steam intothe vessel to contact the fluid and rapidly condense the steam to createacoustic energy; and directing the acoustic energy toward a specificzone within the vessel defining a target zone.
 36. A method forsterilizing water having micro-organisms therein, the method comprising:causing water to flow into an elongated vessel having an inner surfacewhich is shaped to direct acoustic energy; selectively injecting steaminto the vessel at selected points along the vessel and at specificlocations within the vessel such that the steam contacts the water andrapidly condenses to create acoustic energy; and directing the acousticenergy toward a specific zone within the vessel the specific defining atarget zone.